Last week Dianne Hackborn explained some of the Android graphic pipeline internals...
... and then a huge discussion on Google+ broke loose, very good insights!
JSON in Android - Tutorial(vogella.de)
This tutorial explains the basic use of JSON in an Android project.
New Layout Widgets: Space and GridLayout(android-developers.blogspot.com)
The new gridlayout for widgets explained.
Android Section List(code.google.com)
This library provides you iOS style lists with sections on your Android.
Tree View List(code.google.com)
Treeviews for your Android project.
Google Maps Balloons(github.com)
This library provides an easy way to annotate map overlay items with a simple information balloon.
A screencast on how to deal with SQLite databases on Android.
A music app that shares what you're listening with your friends.